XMLHttpRequestEventTarget.onloadstart

The XMLHttpRequestEventTarget.onloadstart is the function called when an XMLHttpRequest transaction starts transferring data.

Syntax

XMLHttpRequest.onloadstart = callback;

Values

  • callback is the function to be called when the transaction begins to transfer data.

Example

var xmlhttp = new XMLHttpRequest(),
  method = 'GET',
  url = 'https://developer.mozilla.org/';

xmlhttp.open(method, url, true);
xmlhttp.onloadstart = function () {
  console.log("Download underway");
};
xmlhttp.send();

Specifications

Specification Status Comment
XMLHttpRequest Living Standard WHATWG living standard

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
onloadstartChrome Full support YesEdge Full support YesFirefox Full support YesIE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown